pearsons



(No Model.) 2 shetsSheet 1.

P. A. PEARSONS. BALANCE BALL FOR SCALES.

Patented N0v.11, 1890.

I No. 440,363.

(No Model.) 2 Sheets-Sheet 2.

P. A. PEARSONS. BALANCE BALL FOR SCALES.

No. 440,363. Patented Nov. 11,1890.

umsmmmm ggllgmagwsmsm UNITED STATES PATENT OFFICE.

FILLMORE A. PEARSONS, OF RUTLAND, VERMONT, ASSIGNOR TO THE HOIYE SCALE COMPANY OF 1886, OF SAME PLACE.

BALANCE-BALL FOR SCALES.

SPECIFICATION forming part of Letters Patent No. 440,363, dated November 11, 1890.

Application filed April 7, 1890. Serial No. 346,857. (No model.)

relate particularly, however, to that portion of the scale known as the balance-ball, which is movably connected to a supporting-bar carried by the scale-beani in rear of its pivot, and which can be adjusted back and forth upon its supporting-bar to proper position to maintain thescale-beam in equilibrium. These balance-balls as heretofore constructed and arranged on the scale-beam consist of a ball or block of suitable metal screw-threaded upon its interior for engagement with corresponding threads upon its supporting-bar,

upon which it is capable of movement longitudinally. In this construction and arrangement the frictional engagement of the screwthread upon the two surfaces has been relied upon for the purpose of retaining the balanceball in its adjusted positions. It has been found in practice, however, that the friction between the two is not sufficient to prevent movement of the ball out of the position to which it is adjusted under certain conditions, such as the removal of the scale from one place of use to another, the abrupt change of position of the scale-beam by the placing of articles of great bulk upon the scaleplae form to be weighed, or the placing of the weights suddenly upon the end of the scalebeam. Under these and many other similar conditions the vibration of the scale-beam and the balance-ball-supporting bar necessarily resulting therefrom often cause a movement in one direction or the other of the balance-ball, and thus destroy the accurate adjustment of the scale-beam, which may or may not be discovered in time to prevent the losses which would result from the use of the scale in such condition.

It is the object of the present invention to provide a balance-ball for a scale-beam which shall be free from this defect and have in addition the advantage over prior constructions of greater cheapness and convenience in manufacture.

To that end the invention consists,briefly, in a balance-ball for a scale-beam, provided with a longitudinal opening at or nearits center for the passage of its supporting-bar, (the latter being screw-threaded or not) and arod of spring metal carried by said ball and having outwardly-sprung arms in contact with opposite sides of said supporting bar, the torsional resistance of the rod through its arms preventing the movement of the ball, except when force is applied directly to the latter, the rod carried by the ball thus performing the function of retaining the ball in adjusted positions, and when the supportingbar is provided with screw-threads performing in addition the function of guiding the ball upon its supporting-bar by the engagement of its arms with the screw-threads upon the bar.

In the drawings accompanying this application, Figure 1 is a side view of the scalebeam of a platform-scale provided with a balance-ball embodying the present invention, the latter being shown partly in section. Fig. 2 is an end view, upon an enlarged scale, of the balance'ball disconnected from the scale beam. Fig. 3 is a section on the line 3 3 of Fig. 2. Fig. a is an end view of the guiding and retaining rod carried by the balance-ball. Figs. 5 to 12 are views illustrating modifications, which will hereinafter be referred to.

Referring to Figs. 1 to I, it will be seen that A represents a familiar form of scale -beam for platformscales, and B its poise. The scale-beam A has mounted upon it at a point in the rear of its pivotal connections to the scale-body a bar (I, screw-threaded, as shown. The bar (I has mounted loosely upon it a balance-ball c, capable of movement longitudinally thereon. The ball 0 is provided with a longitudinal opening of a diameter sufficiently large to permit the free passage through it of the bar (Z. The balance-ball is also provided with a second longitudinal opening for rethe screw-threads heretofore provided upon the interior of the balance-ball. The arms 9 of the rod e are also preferably curved slightly, as will be noticed, so as to conform to the contour of those portions of the rod with which they make contact, and thus support the balance-ball out of contact with its supportingbar and keep all port-ions of its inner surface equally distant from the supporting-bar, as shown in the drawings. When the balanceball 0 is to be placed in position upon its bar at, itsarms g will be sprung outward against the torsional resistance of the rod e-and located upon opposite sides of the'supportingbar, against which they will bear in opposite directions with a pressure sufficient to prevent movement of the balance-ball, except upon the application of forceas by the hand-directly to the balance-ball, any tendency of the ball to move upon the bar due to the vibration of the scale-beam or other s milar causes being further resisted by the engagement of the arms g with the screw-threads upon the supporting-bar.

Instead of being screw-threaded, as described, the surface of the bar d may be simply serrated or roughened to increase the friction between it and the arms 9 of the rod e, or it may be provided with a series of projections for engaging the arms g. In some cases, also, the bar at may have a comparatively smooth surface, in which case the balance-ball 0 will be held in its adjusted positions upon its supporting-bar solely by the friction or binding force of the spring-arms g upon the surface of its supporting-bar d. Such a construction is illustrated in Fig. 6 of thedrawings. In some cases, also, particularly with heavy or large scales, it may be desirable to provide the balance-ball with two rods e and two pairs of outwardly-sprung arms 9. In such a construction the rods 6 will be seated preferably in longitudinal openings or recesses oppositely arranged in the balance-ball. Such construction and arrangement of the rod e and arms 9 are shown in Fig. 5, in which figure the supporting-bar d is shown as screw-threaded. In such a construction, also, the two spring-arms g of each pair will be located, as in the previous figures, so as to bear against opposite sides of the supporting-bar d.

The balance-ball c is shown in the figures of the drawings just described as provided at each end with an enlarged opening f for the reception of the outwardly-sprung arms of the rod e. These openings f, though preferable, may be omitted, and the ends of the rod cl project beyond the ends of the balance opposite sides of the supporting-bar d, engaging its screw-threads.

In the construction illustrated in Figs. 9 to 10 the balance-ball is provided with a rod 6, of spring metal, lying within grooves in the exterior of the balance-ball and extending longitudinally of and surrounding said balance-ball, the rod at its points of contact with the supporting-bar at being bent outwardly, so as to conform to the contour of the supporting-bar and engaging its screw-threads.

In the construction illustrated in Figs. 11 and 12 the balance-ball is provided with a spring-rod e, the main portion of which is coiled about the supporting-bar 01 within its screw-threads, its ends lying within recesses formed in the opposite ends of the balanceball to compel its movement with the balance-ball upon movement of 'the latter back and forth upon the supporting-barin adj ustment. In this construction the coiled portions of the rod eform, in effect, the outwardlysprung arms of the preceding figures of the drawings.

With a construction of balance-ball such as described the screw-threading of the interior of the balance-ball is dispensed with,

and-the cost of production of the balanceballs thus materially decreased, the rodeand its outwardly-sprung arms 9 performing both the. function of these screw-threads, of guiding the balance-ball upon its supporting-bar, and retaining it in the position to which it is moved by the engagement of its arms with the screw-threads or projections upon its supporting-bar. When the supporting-bar is screw-threaded, as shown, or provided with projections, the balance-ball will be turned upon its'supporting-bar, as in prior constructions; but when the supporting-bar has'a smooth surface or is simply roughened, or is provided with mere serrations on its surface, the balance-ball will be slid back and forth upon it without turning, the pressure of the arms 9 of the spring-rod (1 upon the surface of the supporting-bar in opposite directions being in that case relied upon solely for the purpose of retaining the ball in its proper adjusted position on its supporting-bar.

It is obvious that the outwardly-sprung arms g, instead of being both formed from a single piece of spring-wire, may be each formed from one piece, or instead of being formed from such a piece or pieces of springwire extend'inglongitudinally through the ballance-ball may be otherwise secured to or mounted in the balance-ball. It will also be understood that the balance-ball may be of any desired form instead of being circular, as shown.

\Vhat I claim is 1. The combination, with a scale-beam, of a supporting-bar and a balance-ball loosely mounted thereon, provided with a spring-rod engaging opposite sides of the supportingbar, substantially as described.

2. The combination, with a scalebeam, of a supportingbar and a balance-ball loosely mounted thereon, provided with outwardlysprung arms engaging opposite sides of said supporting-bar, substantially as described.

3. The combination, with a scale-beam, of a supporting-bar and a balance-ball loosely mounted thereon, provided with outwardlysprung arms engaging opposite sides of said supporting-bar, the contact portions of said arms being curved to conform to the contour of the supporting-bar, substantially as described.

4. The combination, with a scale-beam, of a supporting-bar and a balance-ball loosely mounted thereon, provided with a spring-rod having outwardly-sprung arms engaging opposite sides of said supporting-bar, substantially as described.

5. The combination, with a scale-beam, of a supporting-bar and a balance-ball loosely mounted thereon, provided with a spring-rod having outwardly-sprung arms engaging opposite sides of said supporting-bar, the contact portions of said arms being curved to con form to'the contour of the supportingbar, substantially as described.

6. The combination, with a scale-beam, of a supporting-bar provided with screw-threads or projections, a balance-ball loosely mounted thereon, provided with a spring-rod having outwardly sprung arms lying within the screWt-hreads or projections 011 said supporting-bar and engaging opposite sides of said bar, substantially as described.

7. The combination, with a balance-ballsupporting bar, of a balance-ball c, loosely mounted thereon and provided with a pair of oppositely-arranged spring-rods, each having outwardly-sprung arms, the arms of each pair engaging opposite sides of said supportingbar, substantially as described.

8. The combination, with the supportingbar (1, of the balance-ball c, the spring-rod 6, carried by said ball and having outwardlysprung arms lying within the screw-threads and engaging opposite sides of the bar (Z, substantially as described.

9. The combination, with a balance-ballsupporting bar, of a balance-ball c, loosely mounted thereon, and a spring-rod e, extending longitudinally of said ball and seated in grooves upon opposite sides of said ball, its end portions engaging opposite sides of the supporting-bar, substantially as described.

10. The combination, with a balance-ballsupporting bar, of a balance-ball c, loosely mounted thereon, and a spring-rod 6, carried by said ball and coiled about said supportingbar, substantially as described.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

- FILLMORE A. PEARSONS.

Witnesses:

JOHN A. MEAD, CHAS. JOHNSON. 

